The invention concerns a support roll for a rolling mill, such as a plate rolling mill, sheet rolling mill or the like, which consists of a shell and a roll shaft/roll spindle, and a method for producing a support roll of this type.
Previously known support rolls for multiple-high rolling stands for hot rolling or cold rolling on a flat track are produced as a single part. To produce support rolls that weigh more than 120 t, which are used especially in plate rolling stands, two possible means of production are known:
(a) The support roll is cast and then forged in an open-die forge and then worked.—single-component roll—
(b) The support roll is cast by composite casting techniques and consists of hard, wear-resistant material in the barrel region and of high-grade tough material with high bending fatigue strength in the neck and core regions. This is followed by mechanical working.—multiple-component roll—
There are only a few manufacturers of single-part support rolls that weigh more than 170 t, and this means long delivery times and high prices.
Support rolls of this type have the further disadvantage of high shipping costs due to the large weights.
Furthermore, the entire roll body must be scrapped when the useful barrel region (constructed to be wear-resistant) becomes worn.
Besides the single-part support rolls, multipart support rolls are also known.
EP 1 056 553 B1 describes a rolling mill with work rolls and multipart support rolls that consist of a main roll body with several roller bearings installed on it side by side in its longitudinal direction, whose outer rings support a rotatable shell that encompasses the roller bearings. The inner surface of the shell rests with full contact on the outer surfaces of the outer rings of the roller bearings. The outer surface forms the roll barrel of the support roll, and three roller bearings are provided on the length of the main roll body, of which the middle roller bearing is designed as a conical roller bearing. The two outer roller bearings are designed as cylindrical roller bearings, and an eccentric bushing that can be rotated by a motor about the longitudinal axis of the main roll body is installed between each of the two cylindrical roller bearings and the main roll body, such that a self-adjustable tilting segment that allows skewing of the cylindrical roller bearing is provided in the load region of the main roll body between the main roll body and each eccentric bushing.
German Early Disclosure 1 602 121 describes a multipart support roll for four-high rolling stands for rolling out flat metal products, in which the rolling forces to be absorbed by the support roll are transmitted from the cylindrical surface of the support roll to the spindle or shaft in only two places within the width range of the roll barrel.
EP 0 896 841 A2 discloses a rolling mill with work rolls and multipart support rolls that consist of a main roll body with several roller bearings installed on it side by side in its longitudinal direction, whose outer rings support a rotatable shell that encompasses the roller bearings. The outer surface forms the roll barrel of the support roll, where the main roll body can rotate about its longitudinal axis and is divided into cylindrical sections that have approximately the same width as the roller bearings. The parallel axes of these adjacent cylindrical sections are offset relative to each other. The inner surface of the shell rests with full contact on the outer surfaces of the outer rings of the roller bearings and in this way is provided with an eccentricity that results from the eccentricity of the sections of the main roll body, reduced by the opposing bending effect of the shell.
An arrangement of this type is also described in EP 1 058 616 B1.
DE 197 02 325 A1 discloses a method for producing vibration-damped rolls. In this method, to change the values of the natural frequencies of at least one roll, at least one cavity that is parallel to the axis is formed in at least one support roll and/or an associated work roll. In a set of rolls of the invention, which consists of at least a work roll and support roll, at least one roll is provided with at least one cavity that is parallel to the axis.
EP 0 937 515 B1 discloses a roll that consists of a rotating roll jacket and means, which are installed inside the roll jacket, for controlling the flexural rigidity of the roll jacket. The control means consist of a sliding bearing in the form of a rotatable body, which can be rotatably adjusted and is shaped in such a way that its load-bearing surface corresponding to the loaded zone of the roll jacket is part of the cylindrical outer surface of a rotationally symmetric body, and the boundary of this cylindrical outer surface is formed in such a way that the width and/or position of the load-bearing surface varies along the circumference of the rotatable body. In the region of its load-bearing surface, the rotatable body has at least one recess. The course of the boundary of this recess and its inner contour can be shaped in any desired way.
These previously known multipart embodiments or designs of support rolls are constructed as shell rolls, i.e., an outer sleeve or the like rotates about an inner shaft, spindle or the like.
Support rolls with a large total weight that are produced by these previously known methods have the same disadvantages with respect to shipping, etc., as a single-part support roll.